JP3909574B2 - Resist coating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist coating device capable of controlling an amount of residual solvent, which causes the fluctuation of the width of a line. <P>SOLUTION: A resist coating unit (COT) is equipped with a spin chuck 71 rotating while retaining a wafer W, a cup 72 surrounding the spin chuck 71, and a resist liquid supply nozzle 73 supplying resist liquid to the wafer W. In the resist coating unit, a plurality of solvent gas supply nozzles 80 capable of supplying solvent gas toward different concentric circles on the surface of the wafer W, mixers 85 capable of adjusting the concentration of the solvent gas supplied by the solvent gas supply nozzles 80 and opening and closing valves V3, for example, capable of adjusting the amount of the solvent gas supplied from the solvent gas supply nozzles 80, are provided to control the vaporizing speed of residual solvent. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a resist coating apparatus capable of controlling the film quality of a resist film formed on the surface of a substrate to be processed such as a semiconductor wafer.
[0002]
[Prior art]
  In general, in the manufacturing process of a semiconductor wafer, a photolithography technique is used to form a resist pattern on the surface of a semiconductor wafer, an LCD substrate, or the like (hereinafter referred to as a wafer). In this photolithography technique, a resist film is formed on a surface of a wafer or the like by supplying (discharging, applying) a resist solution, a resist film forming process for exposing the circuit pattern to the formed resist film, and a post-exposure process. A developing process for supplying (discharging, applying) a developing solution to the wafer or the like and performing a developing process.
[0003]
  In addition, between the above processing steps, for example, a heat treatment performed between the resist coating step and the exposure processing step to evaporate the residual solvent in the resist film and improve the adhesion between the wafer and the resist film. {Pre-bake (PAB)}, in order to prevent the generation of fringe between the exposure process and the development process, or to induce an acid-catalyzed reaction in a chemically amplified resist (CAR) Remove the residual solvent (residual solvent) in the resist and the rinsing liquid taken into the resist during development after the heat treatment {post-exposure bake (PEB)} and development process, and soak in wet etching Various heat treatments such as a heat treatment (post bake) for improving the embedding are performed.
[0004]
  In the photolithography process, as the circuit pattern and line width (CD) become finer, the uniformity of the pattern line width in the wafer surface (CD uniformity) is strictly demanded, which greatly affects the pattern dimension. In addition to the development process and the PEB process which have been performed, it is required to improve the line width variation factor in the process before exposure.
[0005]
  Therefore, in the past, line width variation was improved by improving the film thickness uniformity of the resist film formed on the wafer surface.
[0006]
[Problems to be solved by the invention]
  However, in recent years, even if the resist film thickness is uniform, for example, the amount distribution of resist constituents such as the amount of solvent remaining in the resist film, the ratio distribution difference of protective groups in the resist, and the concentration of polymers in the resist. To improve the film quality uniformity of the resist film because the line width variation due to the film quality change due to the difference in the chemical and physical properties (hereinafter referred to as film quality) of the resist film, such as the state difference, has been confirmed. Has become very important.
[0007]
  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist coating apparatus capable of controlling the residual solvent amount (residual solvent amount) that affects the film quality uniformity.
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, a first resist coating apparatus of the present invention comprises a holding means for holding and rotating a substrate to be processed, a processing container surrounding the holding means, and a resist solution for the substrate to be processed. In a resist coating apparatus comprising a resist solution supply means for supplying, a plurality of solvent gas supply means capable of supplying a solvent gas containing a solvent of the resist solution toward different concentric circles on the surface of the substrate to be processed; and A solvent concentration adjusting means capable of adjusting a solvent concentration of the solvent gas supplied by the solvent gas supplying means; a supply amount adjusting means capable of adjusting a supply amount of the solvent gas supplied by the solvent gas supplying means; and a pressure of the solvent gas. And the solvent concentration adjusting means is connected to a solvent supply source via an on-off valve and to an inert gas supply source via an on-off valve. And, wherein the solvent is volatilized in an inert gas is generated can form the solvent gas (claim 1). Here, the solvent gas means one obtained by volatilizing the solvent (solvent) of the resist solution into an inert gas. In this case, it is preferable that the solvent gas supply means is provided in the processing container or is provided in a nozzle arm that can be advanced and retracted in the processing container (claims 2 and 3). Further, it is preferable that the angle of the solvent gas supply means with respect to the substrate to be processed is adjustable.
[0009]
  In addition, the present invention2The resist coating apparatus includes a holding unit that holds and rotates a substrate to be processed, a processing container that surrounds the holding unit, and a resist solution supply unit that supplies a resist solution to the substrate to be processed. A plurality of gap forming means for forming a fixed gap with the surface of the substrate to be processed, and a position adjusting means for horizontally moving the plurality of gap forming means in the radial direction on the substrate to be processed. And a gap adjusting means capable of adjusting the sizes of the gaps formed by the plurality of gap forming means, respectively.5). In this case, it is preferable to provide a gap temperature adjusting means capable of adjusting the temperature of the gap forming means.6).
[0010]
  According to this invention, since the volatilization rate of the residual solvent (residual solvent) on the substrate to be processed can be controlled, the amount of residual solvent on the surface of the substrate to be processed can be made uniform.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below in detail with reference to the drawings.
[0012]
  1 is a schematic plan view of an embodiment of a resist solution coating / development processing system, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a rear view of FIG.
[0013]
  In the above processing system, a plurality of semiconductor wafers W (hereinafter referred to as “wafers W”) as substrates to be processed are loaded into or out of the system from the outside in units of a plurality of wafer cassettes, for example, 25 wafers. A cassette station 10 (carrying unit) for carrying W in and out, and various single-wafer processing units for performing predetermined processing on the wafer W one by one in the coating and developing process are arranged in multiple stages at predetermined positions. The processing station 20 having the processing apparatus of the present invention and the interface unit 30 for transferring the wafer W between the processing station 20 and an exposure apparatus 40 (EXP) provided adjacent to the processing station 20 are mainly used. The part is composed.
[0014]
  As shown in FIG. 1, the cassette station 10 includes a plurality of, for example, up to four wafer cassettes 1 at the position of the projection 3 on the cassette mounting table 2 with the respective wafer entrances facing the processing station 20 side. Wafer transfer tweezers 4 mounted in a line along the direction and movable in the cassette arrangement direction (X direction) and in the wafer arrangement direction (Z direction) of the wafer W accommodated in the wafer cassette 1 along the vertical direction. Is configured to be selectively transferred to each wafer cassette 1. Further, the wafer transfer tweezers 4 are configured to be rotatable in the horizontal θ direction, and include an alignment unit (ALIM) and an extension unit (EXT) belonging to a multi-stage unit portion of a third group G3 on the processing station 20 side to be described later. ) Can also be transported.
[0015]
  As shown in FIG. 1, the processing station 20 is provided with a vertical transfer type main wafer transfer mechanism 21 at the center, and a set of all the processing units around a chamber 22 that accommodates the main wafer transfer mechanism 21. Alternatively, they are arranged in multiple stages over a plurality of sets. In this example, five sets G1, G2, G3, G4 and G5 have a multistage arrangement, and the first and second sets G1, G2 are arranged in parallel on the front side of the system (front side in FIG. 1). The multistage unit of the third group G3 is arranged adjacent to the cassette station 10, the multistage unit of the fourth group G4 is arranged adjacent to the interface part 30, and the multistage unit of the fifth group G5 is arranged on the back side. Is arranged.
[0016]
  In this case, as shown in FIG. 2, in the first group G1, a predetermined process is performed by placing the wafer W on the spin chuck 71 (holding means) {see FIG. 4} in the cup 23 (processing container). Two spinner type processing units, for example, a resist coating unit (COT) {resist coating apparatus} for supplying a resist solution to the surface of the wafer W to form a resist film and a developing solution for supplying a developer to the surface of the wafer W Developing units (DEV) that perform the above are stacked in two stages in the vertical direction. Similarly, in the second group G2, two spinner type processing units, for example, a resist coating unit (COT) and a developing unit (DEV) are stacked in two stages from the bottom in the vertical direction. The reason why the resist coating unit (COT) is arranged on the lower side in this way is that the drain of the resist solution is troublesome both in terms of mechanism and maintenance. However, the resist coating unit (COT) can be arranged in the upper stage as required.
[0017]
  As shown in FIG. 3, in the third group G3, an oven-type processing unit that performs a predetermined process by placing the wafer W on the wafer mounting table 24, for example, a cooling unit (COL) that cools the wafer W, and the wafer W Adhesion unit (AD) for performing hydrophobic treatment, alignment unit (ALIM) for aligning wafer W, extension unit (EXT) for loading / unloading wafer W, and four hot plate units for baking wafer W (HP) is stacked, for example, in eight steps in order from the bottom in the vertical direction. Similarly, the fourth group G4 is an oven-type processing unit such as a cooling unit (COL), an extension / cooling unit (EXTCOL), an extension unit (EXT), a cooling unit (COL), and two chilling hot plate units having a rapid cooling function. (CHP) and two hot plate units (HP) are stacked in, for example, eight stages in order from the bottom in the vertical direction.
[0018]
  As described above, the cooling unit (COL) and the extension cooling unit (EXTCOL) having a low processing temperature are arranged in the lower stage, and the hot plate unit (HP), the chilling hot plate unit (CHP) and the adhesion unit having a high processing temperature. By disposing (AD) in the upper stage, it is possible to reduce thermal mutual interference between units. Of course, a random multi-stage arrangement is also possible.
[0019]
  As shown in FIG. 1, in the processing station 20, the third and fourth sets G3 and G4 of multistage units (spinner type processing units) adjacent to the first and second sets of G1 and G2 (spinner type processing units) ( Ducts 65 and 66 are vertically cut in the side walls of the oven-type processing unit. Downflow clean air or specially temperature-adjusted air flows through these ducts 65 and 66. By this duct structure, the heat generated in the oven type processing units of the third and fourth groups G3 and G4 is cut off and does not reach the spinner type processing units of the first and second groups G1 and G2. ing.
[0020]
  Further, in this processing system, a fifth stage G5 multi-stage unit can be arranged on the back side of the main wafer transfer mechanism 21 as shown by a dotted line in FIG. The multistage units of the fifth group G5 can move sideways along the guide rail 67 as viewed from the main wafer transfer mechanism 21. Therefore, even when the multi-stage unit of the fifth group G5 is provided, the space portion is secured by sliding the unit, so that the maintenance work can be easily performed from the back with respect to the main wafer transfer mechanism 21.
[0021]
  The interface unit 30 has the same dimensions as the processing station 20 in the depth direction, but is made small in the width direction. A portable pickup cassette 31 and a stationary buffer cassette 32 are arranged in two stages on the front part of the interface part 30, a peripheral exposure device 33 is arranged on the back part, and a wafer is located in the center part. A transfer arm 34 is provided.
[0022]
  The wafer transfer arm 34 is configured to move in the X and Z directions and transfer the cassettes 31 and 32 and the peripheral exposure apparatus 33. Further, the wafer transfer arm 34 is configured to be rotatable in the θ direction, and the wafer delivery on the extension unit (EXT) belonging to the multi-stage unit of the fourth group G4 on the processing station 20 side and on the adjacent exposure apparatus 40 (EXP) side. It is comprised so that it can also convey also to a stand (not shown).
[0023]
  The processing system configured as described above is installed in the clean room 50, and the cleanliness of each part is increased by an efficient vertical laminar flow method in the system.
[0024]
  Next, the operation of the processing system will be described. First, in the cassette station 10, the tweezers 4 for wafer transfer access the cassette 1 containing unprocessed wafers W on the cassette mounting table 2, and take out one wafer W from the cassette 1. When the wafer tweezers 4 takes out the wafer W from the cassette 1, it moves to the alignment unit (ALIM) arranged in the multi-stage unit of the third group G3 on the processing station 20 side, and in the unit (ALIM) A wafer W is placed on the wafer mounting table 24. The wafer W undergoes orientation flat alignment and centering on the wafer mounting table 24. Thereafter, the main wafer transfer mechanism 21 accesses the alignment unit (ALIM) from the opposite side, and receives the wafer W from the wafer mounting table 24.
[0025]
  In the processing station 20, the main wafer transfer mechanism 21 first carries the wafer W into an adhesion unit (AD) belonging to the multistage unit of the third group G3. Within this adhesion unit (AD), the wafer W is subjected to a hydrophobic treatment. When the hydrophobization process is completed, the main wafer transfer mechanism 21 unloads the wafer W from the adhesion unit (AD), and then cools the cooling units (belonging to the third group G3 or the fourth group G4 multi-stage unit). COL). In this cooling unit (COL), the wafer W is cooled to a set temperature before the resist coating process, for example, 23 ° C. When the cooling process is completed, the main wafer transfer mechanism 21 unloads the wafer W from the cooling unit (COL), and then to the resist coating unit (COT) belonging to the first group G1 or the second group G2 multistage unit. Carry in. In this resist coating unit (COT), the wafer W is coated with a resist with a uniform film thickness on the wafer surface by spin coating.
[0026]
  When the resist coating process is completed, the main wafer transfer mechanism 21 unloads the wafer W from the resist coating unit (COT) and then loads it into the hot plate unit (HP). In the hot plate unit (HP), the wafer W is mounted on a mounting table and pre-baked at a predetermined temperature, for example, 100 ° C. for a predetermined time. Thus, the residual solvent (solvent) can be removed by evaporation from the coating film on the wafer W. When pre-baking is completed, the main wafer transfer mechanism 21 unloads the wafer W from the hot plate unit (HP), and then transfers the wafer W to the extension cooling unit (EXTCOL) belonging to the multistage unit of the fourth group G4. Within this unit (COL), the wafer W is cooled to a temperature suitable for the peripheral exposure process in the next process, that is, the peripheral exposure apparatus 33, for example, 24 ° C. After this cooling, the main wafer transfer mechanism 21 transfers the wafer W to the extension unit (EXT) immediately above, and places the wafer W on a mounting table (not shown) in the unit (EXT). When the wafer W is mounted on the mounting table of the extension unit (EXT), the wafer transfer arm 34 of the interface unit 30 accesses from the opposite side to receive the wafer W. Then, the wafer transfer arm 34 carries the wafer W into the peripheral exposure apparatus 33 in the interface unit 30. Here, the wafer W is exposed to the edge portion. Note that a film thickness measuring device may be provided in the peripheral exposure apparatus 33 to periodically measure the film thickness of the wafer W to inspect the film thickness uniformity or film quality uniformity.
[0027]
  When the peripheral exposure is completed, the wafer transfer arm 34 unloads the wafer W from the peripheral exposure apparatus 33 and transfers it to a wafer receiving table (not shown) on the side of the adjacent exposure apparatus 40 (EXP). In this case, the wafer W may be temporarily stored in the buffer cassette 32 before being transferred to the exposure apparatus 40 (EXP).
[0028]
  When the entire exposure is completed in the exposure apparatus 40 (EXP) and the wafer W is returned to the wafer receiving table on the exposure apparatus 40 (EXP) side, the wafer transfer arm 34 of the interface unit 30 accesses the wafer receiving table. The wafer W is received, and the received wafer W is loaded into an extension unit (EXT) belonging to the multi-stage unit of the fourth group G4 on the processing station 20 side, and placed on the wafer receiving table. Also in this case, the wafer W may be temporarily stored in the buffer cassette 32 in the interface unit 30 before being transferred to the processing station 20 side.
[0029]
  The wafer W placed on the wafer receiving table is transferred to the chilling hot plate unit (CHP) by the main wafer transfer mechanism 21 to prevent fringes, or an acid catalyst in the chemically amplified resist (CAR). A post-exposure bake (PEB) treatment is applied to induce the reaction.
[0030]
  Thereafter, the wafer W is carried into a developing unit (DEV) belonging to the multistage unit of the first group G1 or the second group G2. In the developing unit (DEV), the wafer W is placed on a spin chuck, and the developer is uniformly applied to the resist on the surface of the wafer W by, for example, a spray method. When the development is completed, a rinse solution is applied to the surface of the wafer W to wash away the developer.
[0031]
  When the developing process is completed, the main wafer transfer mechanism 21 unloads the wafer W from the developing unit (DEV), and then the hot plate unit (HP) belonging to the third group G3 or the multistage unit of the fourth group G4. Carry in. In this unit (HP), the wafer W is post-baked for a predetermined time at 100 ° C., for example. Thereby, the resist swollen by development is cured, and chemical resistance is improved.
[0032]
  When the post-baking is completed, the main wafer transfer mechanism 21 unloads the wafer W from the hot plate unit (HP), and then loads it into one of the cooling units (COL). Here, after the wafer W returns to room temperature, the main wafer transfer mechanism 21 next transfers the wafer W to the extension unit (EXT) belonging to the third group G3. When the wafer W is mounted on a mounting table (not shown) of the extension unit (EXT), the wafer transfer tweezers 4 on the cassette station 10 side accesses from the opposite side and receives the wafer W. The wafer transfer tweezers 4 put the received wafer W into a predetermined wafer storage groove of the processed wafer storage cassette 1 on the cassette mounting table, and the processing is completed.
[0033]
  Next, the configuration of the resist coating unit (COT) {resist coating apparatus} in the present invention will be described.
[0034]
  As shown in FIG. 4, the resist coating unit (COT) surrounds, for example, a spin chuck 71 (holding means) for rotating and holding the wafer W, and the outside and lower side of the spin chuck 71, and an upper portion is opened. It is mainly composed of a cup 72 (processing container) and a resist solution supply nozzle 73 (resist solution supply means) that can move to a position above the spin chuck 71 and can supply (discharge and apply) a resist solution to the wafer W. It is configured.
[0035]
  The spin chuck 71 is formed of a heat-resistant synthetic resin member made of, for example, polyether ether ketone (PEEK), and a mounting portion 71a capable of holding the lower surface of the wafer W by vacuum suction, and the mounting portion 71a. The rotary shaft 71b is connected to a rotation driving means, for example, a motor M. In this case, the motor M is formed by a servo motor, for example, and the number of rotations is controlled based on a signal programmed in advance. The rotating shaft 71b is formed so as to move up and down by driving a lifting cylinder (not shown) or the like so that the wafer W can be delivered to and from the main wafer transfer mechanism 21.
[0036]
  The cup 72 is formed of, for example, a stainless steel member, and has a tapered surface 72b in which the upper portion of the side wall 72a is reduced in diameter toward the upper side.
[0037]
  The resist solution supply nozzle 73 communicates with a resist solution supply source 76 that stores the resist solution via a resist solution supply pipe 74. Further, in the resist solution supply line 74, in order from the resist solution supply source 76 side, an opening / closing valve V 1, a pressure feeding means for pumping the resist solution, for example, a pump 75, and a resist solution supply amount supplied to the surface of the wafer W are provided. When the resist solution supply amount adjusting means, for example, the mass flow controller C1 and the resist solution supply nozzle 73 stop supplying the resist solution, the resist solution remaining in the supply portion 73a of the resist solution supply nozzle 73 is sucked and supplied. A processing liquid suction means for suppressing dripping from the port 73b, for example, a suck back valve SV is interposed.
[0038]
  The resist solution supply nozzle 73 is integrally formed with a solvent supply nozzle 77 capable of supplying a solvent of the resist solution at an adjacent position. The solvent supply nozzle 77 is connected to a solvent tank 79 via a solvent supply line 78, and controls the pressurization of nitrogen gas or the like supplied into the solvent tank 79 to remove the solvent in the solvent tank 79. The solvent can be supplied from the solvent supply nozzle 77 to the surface of the wafer W. The solvent supply pipe 78 is provided with a mass flow controller C2 capable of adjusting the amount of solvent supplied and an on-off valve V2.
[0039]
  Next, the operation mode of the resist coating unit (COT) configured as described above will be described below.
[0040]
  When the main wafer transfer mechanism 21 loads the wafer W, the spin chuck 71 is lifted out of the cup 72 by the lift cylinder and holds the wafer W by vacuum suction.
[0041]
  Next, when the spin chuck 71 is lowered to a predetermined position in the cup 72, the wafer W on the spin chuck is rotated at a lower speed than the normal rotation at the time of processing, for example, 200 to 800 rpm by driving the motor. A solvent is supplied (dropped, applied) to the surface of W for a predetermined time, for example, 20 seconds. Note that the solvent may be supplied in a stationary state without rotating the wafer W and then rotated.
[0042]
  After supplying the solvent in this way, the supply of the solvent is stopped in a state where the rotation speed of the spin chuck 71 is maintained at the low speed rotation speed. At this time, the solvent is diffused and applied to the entire surface of the wafer W.
[0043]
  Next, the spin chuck 71 is rotated at a high speed, for example, 1000 rpm, and at the same time, for example, 8 cc of resist solution is supplied (dropped, applied) from the resist solution supply nozzle 73 moved above the center of the wafer W, for example, A resist film is formed.
[0044]
  Thereafter, in order to promote drying of the resist film spread on the surface of the wafer W, the wafer W is rotated at a predetermined rotation speed for a certain time (hereinafter referred to as drying rotation), and then the rotation is stopped to complete the resist coating process. To do. When the resist coating process is completed, the spin chuck 71 is raised, and the wafer W is transferred to the main wafer transfer mechanism 21 and transferred to the next process.
[0045]
  The resist coating apparatus of the present invention will be described below with reference to FIGS.
[0046]
  ◎ First embodiment
  In the first embodiment of the present invention, in the resist coating unit (COT) configured as described above, a plurality of solvent gas supplies capable of supplying (discharging and spraying) solvent gas toward different concentric circles on the surface of the wafer W are provided. Nozzle 80 (solvent gas supply means), mixer 85 (solvent concentration adjustment means) capable of adjusting the solvent concentration of the solvent gas supplied by the solvent gas supply nozzle 80, and supply of solvent gas supplied by the solvent gas supply nozzle 80 For example, a mass flow controller C3 (supply amount adjusting means) capable of adjusting the amount is provided.
[0047]
  In this case, a plurality of solvent gas supply nozzles 80 are provided on the tapered surface 72b in the cup 72, for example, four on each of the opposing tapered surfaces 72b as shown in FIG. The solvent gas supply nozzles 80 are provided with their angles adjusted so that the solvent gas can be supplied toward different concentric circles on the surface of the wafer W.
[0048]
  As shown in FIG. 5, the mixer 85 is connected to a solvent supply source 83 via an on-off valve V3, and is connected to an inert gas supply source 84 via an on-off valve V4. It is formed so that a solvent gas can be generated by stably volatilizing the solvent into an inert gas by a heater or the like (not shown) having the above. The mixer 85 is provided with, for example, a vaporization concentration control valve (not shown) capable of adjusting the concentration of the solvent contained in the solvent gas, and the solvent gas is supplied to the solvent gas based on a control signal from the CPU 100 described later. The concentration of the contained solvent can be adjusted to a predetermined concentration that controls the volatilization of the residual solvent (residual solvent) of the wafer W described later.
[0049]
  Further, as shown in FIG. 5, the solvent gas supply nozzle 80 and the mixer 85 are connected by a solvent gas supply pipe 82, and the solvent gas supply pipe 82 is connected in order from the solvent gas supply nozzle 80 side. A mass flow controller C3 that can measure the flow rate (supply amount) of the solvent gas and adjust the supply amount (flow rate) of the solvent gas, and a pressure regulator 86 such as a regulator that can adjust the pressure of the solvent gas. It is installed.
[0050]
  Further, the on-off valves V3, V4, the mixer 85, the pressure regulator 86, and the mass flow controller C3 are electrically connected to control means such as the CPU 100, respectively, and according to the amount of residual solvent of the wafer W determined in advance, The concentration of the solvent contained in the solvent gas, the pressure of the solvent gas, the flow rate (supply amount) of the solvent gas, and the like can be controlled.
[0051]
  By configuring the resist coating unit (COT) in this way, for example, when the volatilization rate of the residual solvent (residual solvent) at the center of the wafer W is smaller than the volatilization rate of the residual solvent at the peripheral portion, By supplying (spraying) solvent gas with low solvent concentration to the part to promote volatilization of residual solvent, and supplying (spraying) solvent gas with high solvent concentration to the peripheral part to suppress volatilization of residual solvent Since the volatilization rate of the residual solvent on the substrate to be processed which volatilizes during the drying rotation can be adjusted, the amount of residual solvent on the surface of the substrate to be processed can be made uniform. That is, the film quality uniformity can be improved.
[0052]
  Further, as shown in FIGS. 6A and 6B, the volatilization rate of the residual solvent in the resist film of the wafer W is not constant during the drying rotation and decreases with time, that is, with the decrease of the residual solvent. .
[0053]
  On the other hand, as a result of intensive studies by the present inventors, when the residual solvent amount after drying rotation is uniform within the surface of the wafer W, the volatilization rate during drying rotation in the surface, particularly the volatilization rate at the initial stage of drying rotation. It has been found that the film quality becomes more uniform when a constant speed (hereinafter referred to as an ideal volatilization speed) is changed depending on the type of resist.
[0054]
  Therefore, if the concentration and supply amount of the solvent gas supplied by the solvent gas supply nozzle 80 during the drying rotation of the wafer W are controlled by the CPU 100, the uniformity of the film quality can be further improved.
[0055]
  For example, as shown in FIGS. 6A and 6B, when the volatilization rate is smaller than the ideal volatilization rate (one-dot chain line), the solvent gas solvent supplied to the surface of the wafer W by the solvent gas supply nozzle 80. The concentration is adjusted to 0% by the mixer 85, that is, only the inert gas, and the supply amount of the inert gas is adjusted by the mass flow controller C3 as shown by the broken lines in FIGS. The speed may be increased to approach the ideal volatilization speed.
[0056]
  In addition, as shown in FIG. 6B, when the volatilization rate is higher than the ideal volatilization rate, the solvent concentration of the solvent gas supplied from the solvent gas supply nozzle 80 to the surface of the wafer W is adjusted by the mixer 85. In addition, as shown by the solid line in FIG. 6D, the supply amount of the solvent gas may be adjusted by the mass flow controller C3, and the volatilization rate may be reduced so as to approach the ideal volatilization rate.
[0057]
  With this configuration, the volatilization rate at the initial stage of drying rotation can be adjusted to the ideal volatilization rate, so that the film quality uniformity can be further improved.
[0058]
  In the above description, the case where the solvent gas supply nozzle 80 is provided on the tapered surface 72b in the cup 72 has been described. However, the position where the solvent gas supply nozzle 80 is provided is not limited to this, and the cup 72 can move forward and backward. A plurality of nozzle arms 88 may be provided (see FIG. 7).
[0059]
  In this case, the nozzle arm 88 is moved up and down by a moving means (not shown) constituted by, for example, a motor and a ball screw mechanism that can move horizontally on the cup 72, and by an air cylinder or the like that can move up and down on the cup 72. What is necessary is just to comprise with a means (not shown).
[0060]
  Further, if the solvent gas supply nozzle 80 is provided with an angle adjusting means capable of adjusting its angle, the type (shape, size, etc.) of the wafer W, the type of the resist solution, or the residual solvent of the wafer W during the drying rotation. Depending on the amount, the angle of the solvent gas supply nozzle 80 can be changed for processing.
[0061]
  Next, a resist film forming method when the solvent gas supply nozzle 80 is provided on the nozzle arm 88 will be described with reference to FIG.
[0062]
  First, when the wafer W is loaded into the cup 72, the nozzle arm 88 is temporarily kept outside the cup 72 in order to avoid interference with the main wafer transfer mechanism 21, and the spin chuck 71 is raised to raise the wafer. W is received from the main wafer transfer mechanism 21. The spin chuck 71 sucks and holds the received wafer W and then descends into the cup 72 {FIG. 7A}.
[0063]
  Next, the resist solution supply nozzle 73 is moved above the wafer W to supply the resist solution to the surface of the wafer W, and the spin chuck 71 is rotated to form a resist film {FIG. 7B}.
[0064]
  When the resist film is formed, the resist solution supply nozzle 73 is moved from above the wafer W to a standby position (not shown), and the spin chuck 71 starts drying rotation. When the drying rotation starts, the nozzle arm 88 is moved above the wafer W {FIG. 7 (c)}.
[0065]
  During the drying rotation, each solvent gas supply nozzle 80 supplies (discharges and sprays) solvent gases having different solvent concentrations toward different concentric circles on the surface of the wafer W based on the control signal of the CPU 100. The residual solvent volatilization rate is controlled {FIG. 7 (d)}.
[0066]
  When the drying process is completed, the nozzle arm 88 is retracted out of the cup 72 {FIG. 7 (e)}, and then the edge rear surface of the wafer W is rinsed.
[0067]
  Thereafter, the spin chuck 71 is raised, and the wafer W is unloaded from the resist coating unit (COT) by the main wafer transfer mechanism 21 to complete the resist coating process.
[0068]
  ◎First reference embodiment
  Of this inventionFirst reference embodimentIn the resist coating unit (COT), a top plate 90 having a different thickness on the lower surface side on different concentric circles is provided above the spin chuck 71 to control the volatilization rate of the residual solvent.
[0069]
  For example, when the volatilization rate of the residual solvent at the peripheral edge of the wafer W during the drying rotation is larger than the volatilization rate of the residual solvent at the center, the wafer W held on the spin chuck 71 as shown in FIG. In addition, a top plate 90 having substantially the same shape as the wafer W having a tapered concave portion that expands toward the lower surface may be provided close to the upper side of the wafer W.
[0070]
  If the top plate 90 is configured in this manner, the space above the peripheral edge of the wafer W becomes narrow, so that the volatilized solvent is difficult to diffuse, the solvent concentration in the processing atmosphere is increased, and the volatilization rate of the solvent is suppressed. On the other hand, since the space on the wafer W is wide at the center of the wafer W, the volatilized solvent easily diffuses, and the concentration of the solvent in the processing atmosphere does not increase that much, so the volatilization rate of the residual solvent is not suppressed. Therefore, the residual solvent amount on the surface of the wafer W can be made uniform by adjusting the volatilization rate of the central portion and the peripheral portion of the wafer W.
[0071]
  The top plate 90 may be detachably provided on a top plate transfer arm that can move forward and backward inside and outside of the cup 72, or a cup is provided on the cup 72 and is provided detachably on the lower surface of the lid. Also good.
[0072]
  In this case, the top plate 90 is positioned above the wafer W in the cup 72 during the drying rotation after the resist application, as in the case of the solvent gas supply nozzle 80 held by the nozzle arm 88 of the first embodiment. It is moved, and after the drying rotation for a predetermined time, it is retracted out of the cup 72.
[0073]
  Further, the top plate 90 is not limited to a taper concave shape whose cross section expands toward the bottom surface, and for example, the top plate 91 whose bottom surface is formed in a stepped cross section and whose center is thinnest {FIG. a)}. Further, when the volatilization rate of the residual solvent at the center of the wafer W during the drying rotation is larger than the volatilization rate of the residual solvent at the peripheral part, the top plate is formed in a tapered convex shape whose diameter is reduced to the lower surface side. 92 {Fig. 9 (b)}, or the top plate 93 {Fig. 9 (c)} having the thickest central portion with the lower surface side being stepped in cross section. Of course, other various shapes such as the top plate 94 shown in FIG. 9D can be used according to the residual solvent amount or the volatilization rate of the resist film.
[0074]
  Further, if the top plate 90 is provided with a top plate lifting means so that the top plate 90 can be moved up and down, and the distance between the top plate 90 and the wafer W is adjusted during the drying rotation, the volatilization rate can be controlled more reliably. can do.
[0075]
  Further, if the top plate 90 is provided with a top plate temperature adjusting means such as a heater so that the temperature on the different concentric circles of the top plate can be adjusted, the volatilization rate of the central portion and the peripheral portion of the wafer W can be more reliably increased. Can be controlled.
[0076]
  ◎Second reference embodiment
  Of this inventionSecond reference embodimentIn the resist coating unit (COT), a top plate 95 having different open areas on different concentric circles is provided above the spin chuck 71 to control the volatilization rate of the residual solvent.
[0077]
  For example, when the volatilization rate of the residual solvent at the center portion of the wafer W during the drying rotation is smaller than the volatilization rate of the residual solvent at the peripheral portion, as shown in FIG. For example, the spin chuck 71 holds a top plate 95 using porous materials 95a and 95b with an aperture ratio of about 10 to 40% and using a metal 95c with an aperture ratio of 0% such as aluminum or stainless steel at the peripheral portion. What is necessary is just to provide on the wafer W to be processed.
[0078]
  By configuring the top plate 95 in this manner, the aperture ratio of the porous materials 95a and 95b is high above the center of the wafer W, so that the volatilized solvent diffuses through the porous materials 95a and 95b. On the other hand, since the volatilized solvent is blocked by the metal 95c above the peripheral edge, the concentration of the solvent in the processing atmosphere increases. Therefore, the residual solvent amount on the surface of the wafer W can be made uniform by adjusting the volatilization rate between the central portion and the peripheral portion of the wafer W.
[0079]
  In the above description, the case where the top plate 95 is formed of a porous material and a metal has been described. However, the top plate 95 is not limited to this, and for example, a solvent vapor ( It is also possible to use a plurality of vent holes through which a solvent vapor) can pass and which have different numbers and sizes of vent holes on different concentric circles.
[0080]
  Further, the aperture ratio of the top plate 95 can be freely changed in accordance with the volatilization rate of the residual solvent. For example, the volatilization rate of the residual solvent at the center of the wafer W during the drying rotation is determined by the residual solvent at the peripheral portion. When the volatilization rate is higher than the volatilization rate, it is possible to form the aperture ratio of the central part smaller than the aperture ratio of the peripheral part.
[0081]
  Furthermore, if the shape of the top plate 95 is formed so that the thickness of the lower surface side is different on different concentric circles,First reference embodimentIn the same manner as described above, it is possible to control the volatilization rate of the residual solvent by changing the size of the space above the wafer W {see FIG. 10B}. Also,First reference embodimentSimilarly to the above, it is of course possible to provide the top plate 95 with a top plate elevating means and a top plate temperature adjusting means.
[0082]
  ◎Second embodiment
  Of this inventionSecond embodimentIn the resist coating unit (COT), a plurality of blocks 110 (gap forming means) that form a certain gap on the wafer W and a block arm that can horizontally move the block 110 in the radial direction on the wafer W, respectively. 111 (position adjusting means) and block raising / lowering means 112 (interval adjusting means) capable of adjusting the size of the gap formed by the block 110 are provided to control the volatilization rate of the residual solvent. is there.
[0083]
  As shown in FIGS. 11 and 12, the block 110 is formed in a cylindrical shape whose lower surface is parallel to the surface of the wafer W, for example, and the residual solvent is volatilized by keeping a certain gap from the wafer W during the drying rotation. Can be suppressed. The block 110 is formed of a material such as aluminum or stainless steel.
[0084]
  As shown in FIG. 11, four block lifting means 112 are provided, for example, at regular intervals at positions where the wafer W is not interfered when held by the spin chuck 71, and are constituted by, for example, a motor and a ball screw mechanism. The block 110 is moved up and down by driving an elevating means (not shown), and the gap between the lower surface of the block 110 and the surface of the wafer W can be adjusted.
[0085]
  As shown in FIG. 11, one end of the block arm 111 is formed so as to be able to hold the block 110, and the other end is connected to the upper portion of the block lifting / lowering means 112, and a rotation means such as a motor (not shown) is provided. By driving, the block arm 111 is formed to be horizontally movable in the radial direction of the wafer W. Further, the block arm 111 is formed in such a length that the block 110 can pass over the rotation center of the spin chuck during rotation.
[0086]
  Next, a processing method using the resist coating unit (COT) configured as described above will be described.
[0087]
  First, before the resist solution supply nozzle 73 starts supplying the resist solution, the block 110 is positioned approximately 30 mm above the surface of the wafer W at the standby position on the outer periphery of the wafer W as shown in FIG. Waiting to
[0088]
  Next, when the resist solution supply nozzle 73 starts supplying the resist solution, the block arm 111 is rotated by a predetermined angle by driving the rotating means as shown in FIG. Move to a predetermined position above W.
[0089]
  When the block 110 moves to a predetermined position, the block elevating means 112 descends the block 110 as shown in FIG. 12C, and a predetermined interval, for example, 0, between the lower surface of the block 110 and the surface of the wafer W. Adjust to form a gap of 3 to 3 mm.
[0090]
  When the predetermined time has elapsed, the block 110 is moved to the next position by the block arm 111 and the size of the gap is adjusted by driving the block elevating means 112.
[0091]
  In this manner, after the plurality of blocks 110 are moved to various positions during the resist solution coating process or during the drying rotation, the block 110 is finally returned to the standby position, and the resist coating process is completed.
[0092]
  By configuring in this way, it is possible to control the volatilization rate of the residual solvent by changing the position and size of the gap formed on the surface of the wafer W during drying rotation, so that the residual solvent amount on the surface of the wafer W is uniform. Can be.
[0093]
  In addition, if the temperature control water conduit which can flow the water etc. which were temperature-controlled at 15-30 degreeC, for example is provided in the block 110 spirally, the temperature of the block 110 can be adjusted, and it is more reliable. The volatilization of the residual solvent can be controlled.
[0094]
  In the above description, the block 110 has a cylindrical shape. However, the shape of the block 110 is not limited to this, and any shape that forms a certain gap on the wafer W can be used, for example, It is also possible to form a hemisphere or the like.
[0095]
  ◎Third reference embodiment
  Of this inventionThird reference embodimentIn the resist coating unit (COT), the air cleaning unit 120 is divided into a plurality of regions and can supply clean air toward the surface of the wafer W, and the temperature of the air supplied by the air cleaning unit 120 is set in each region. A plurality of temperature controllers (air temperature adjusting means) that can be adjusted for each, a plurality of thermocouples 122 (temperature detecting means) that can detect the temperature near the surface on different concentric circles of the wafer W, and the thermocouple 122 This is a case where a CPU 100 (control means) for controlling the temperature controller is provided based on the detected signal to control the volatilization rate of the residual solvent.
[0096]
  As shown in FIG. 13, the air cleaning means 120 is divided into a plurality of regions on different concentric circles, for example, three regions 120a, 120b, and 120c, and is cleaned by, for example, a ULPA filter that can remove particles and the like. It is formed so that air can be supplied to the surface of the wafer W.
[0097]
  As shown in FIG. 13, each region 120a, 120b, 120c of the air cleaning means 120 is connected to an air supply source 126 via air supply pipes 124a, 124b, 124c, for example, a fan or a pump. The air supply means 125a, 125b, 125c and the like are formed so that a predetermined amount of air can be supplied to each of the regions 120a, 120b, 120c.
[0098]
  The air supply pipes 124a, 124b, and 124c are provided with temperature controllers 121a, 121b, and 121c between the regions 120a, 120b, and 120c and the air supply means 125a, 125b, and 125c, respectively. Based on a control signal from the CPU 100, the air temperature can be adjusted.
[0099]
  As shown in FIG. 13, a plurality of, for example, three thermocouple transfer arms 123 extending in the radial direction of the wafer W held by the spin chuck 71 are provided near the surface on different concentric circles of the wafer W. For example, it is formed so that a temperature at a height position of about 2 to 3 mm from the surface of the wafer W can be detected.
[0100]
  The thermocouple 122 is electrically connected to a CPU 100 described later, and is formed so that the detected temperature can be transmitted to the CPU 100.
[0101]
  Further, the thermocouple transfer arm 123 is provided so as to penetrate the cup 72, and is configured to be horizontally movable in the radial direction above the wafer W by driving means constituted by, for example, a motor and a ball screw mechanism. .
[0102]
  By configuring the thermocouple transfer arm 123 in this way, when the wafer W is loaded / unloaded, as shown in FIG. 14A, the wafer W and the thermocouple transfer arm 123 do not interfere with each other, for example, a thermocouple. The tip of the transfer arm 123 can be retracted to a position outside the outer periphery of the wafer W held by the spin chuck 71, and during the resist coating process, as shown in FIG. The tip of 123 can move horizontally to a position above the center of the wafer W held by the spin chuck 71.
[0103]
  The CPU 100 is configured to be able to control the temperature controllers 121a, 121b, and 121c based on the detection signal detected by the thermocouple 122 and the pre-stored correlation information between the solvent volatilization rate and temperature.
[0104]
  By configuring as described above, the volatilization rate can be controlled on different concentric circles on the surface of the wafer W by the temperature of the air supplied by each of the regions 120a, 120b, and 120c of the air cleaning means 120. This resist film can be formed.
[0105]
  If the air cleaning means 120 is provided with an elevating means for air cleaning means constituted by, for example, a motor and a ball screw mechanism so that the air cleaning means 120 can be raised and lowered during the resist coating process, the surface of the wafer W can be more reliably secured. The volatilization rate can be controlled by adjusting the temperature.
[0106]
  In the above embodiment, the case where the substrate to be processed is a semiconductor wafer has been described. However, the present invention can also be applied to an LCD substrate, a photomask reticle substrate, or the like other than the wafer.
[0107]
【The invention's effect】
  As described above, according to the present invention, since the volatilization rate of the residual solvent (residual solvent) on the substrate to be processed can be controlled, the amount of residual solvent on the surface of the substrate to be processed can be made uniform. . Therefore, the pattern line width can be made uniform.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an example of a resist solution coating / development processing system according to the present invention.
FIG. 2 is a schematic front view of the resist solution coating / developing system.
FIG. 3 is a schematic rear view of the resist solution coating / developing system.
FIG. 4 is a schematic configuration diagram showing a main part of the resist coating apparatus of the present invention.
FIG. 5 is a schematic configuration diagram showing a resist coating apparatus according to the first embodiment of the present invention.
FIG. 6 is a graph illustrating a processing method using the resist coating apparatus according to the first embodiment of the present invention.
FIG. 7 is a schematic explanatory diagram for explaining an operation mode of a nozzle arm in the present invention.
FIG. 8 of the present inventionFirst reference embodimentIt is a schematic block diagram which shows the resist coating apparatus.
FIG. 9 shows the present invention.First reference embodimentIt is sectional drawing which shows the shape of the top plate in.
FIG. 10 shows the present invention.Second reference embodimentIt is a schematic block diagram which shows the resist coating apparatus.
FIG. 11 shows the present invention.Second embodimentIt is a schematic block diagram which shows the resist coating apparatus.
FIG. 12 shows the present invention.Second embodimentIt is a schematic block diagram explaining the processing method using this resist coating apparatus.
FIG. 13 shows the present invention.Third reference embodimentIt is a schematic block diagram which shows the resist coating apparatus.
FIG. 14 shows the present invention.Third reference embodimentIt is a schematic block diagram which shows the operation | movement aspect of the thermocouple conveyance arm in.
[Explanation of symbols]
  W Semiconductor wafer (substrate to be processed)
  V3 On-off valve (supply amount adjusting means)
  71 Spin chuck (holding means)
  72 cups (processing containers)
  73 resist solution supply nozzle (resist solution supply means)
  80 Solvent gas supply nozzle (solvent gas supply means)
  85 Mixer (solvent concentration control means)
  88 Nozzle arm
  90, 91, 92, 93, 94 Top plate
  95 Top plate
  100 CPU (control means)
  110 blocks (gap forming means)
  111 block arm (position adjustment means)
  112 Elevating means for block (spacing adjusting means)
  120 Air cleaning means
  120a, 120b, 120c area
  121a, 121b, 121c Temperature controller (air temperature adjusting means)
  122 Thermocouple (Temperature detection means)

Claims (6)

In a resist coating apparatus comprising: a holding unit that holds and rotates a substrate to be processed; a processing container that surrounds the holding unit; and a resist solution supply unit that supplies a resist solution to the substrate to be processed.
A plurality of solvent gas supply means capable of supplying a solvent gas containing a solvent of the resist solution toward different concentric circles on the surface of the substrate to be processed;
A solvent concentration adjusting means capable of adjusting the solvent concentration of the solvent gas supplied by the solvent gas supplying means;
A supply amount adjusting means capable of adjusting a supply amount of the solvent gas supplied by the solvent gas supply means;
A pressure regulator capable of adjusting the pressure of the solvent gas, and
The solvent concentration adjusting means is connected to a solvent supply source via an on-off valve and connected to an inert gas supply source via an on-off valve, and generates a solvent gas by volatilizing the solvent into an inert gas. A resist coating apparatus characterized by being formed. The resist coating apparatus according to claim 1,
The resist coating apparatus, wherein the solvent gas supply means is provided in a processing container. The resist coating apparatus according to claim 1,
The resist coating apparatus, wherein the solvent gas supply means is provided in a nozzle arm that can move forward and backward in a processing container. In the resist coating apparatus according to any one of claims 1 to 3,
A resist coating apparatus, wherein the angle of the solvent gas supply means with respect to the substrate to be processed is adjustable. In a resist coating apparatus comprising: a holding unit that holds and rotates a substrate to be processed; a processing container that surrounds the holding unit; and a resist solution supply unit that supplies a resist solution to the substrate to be processed.
A plurality of gap forming means for forming a fixed gap with the surface of the substrate to be processed;
Position adjusting means capable of horizontally moving the plurality of gap forming means in the radial direction on the substrate to be processed;
Interval adjusting means capable of adjusting the sizes of the gaps formed by the plurality of gap forming means,
A resist coating apparatus comprising: The resist coating apparatus according to claim 5 , wherein
A resist coating apparatus comprising a gap temperature adjusting means capable of adjusting the temperature of the gap forming means.

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